Mysterious source of high-energy cosmic radiation discovered

Published: Thursday, November 20, 2008, 14:26 [IST]

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Washington, Nov 20 : Scientists have announced the discovery of a previously unidentified nearby source of high-energy cosmic rays, which was made with a NASA-funded balloon-borne instrument high over Antarctica.

The team that made the discovery comprised of researchers from the Advanced Thin Ionization Calorimeter (ATIC) collaboration, led by scientists at Louisiana State University, Baton Rouge, US.

The new results show an unexpected surplus of cosmic ray electrons at very high energy - 300-800 billion electron volts - that must come from a previously unidentified source or from the annihilation of very exotic theoretical particles used to explain dark matter.

"This electron excess cannot be explained by the standard model of cosmic ray origin," said John P. Wefel, ATIC project principal investigator and a professor at Louisiana State. "There must be another source relatively near us that is producing these additional particles," he added.

According to the research, this source would need to be within about 3,000 light years of the sun.

It could be an exotic object such as a pulsar, mini-quasar, supernova remnant or an intermediate mass black hole.

"Cosmic ray electrons lose energy during their journey through the galaxy," said Jim Adams, ATIC research lead at NASA's Marshall Space Flight Center in Huntsville, Alabama. These losses increase with the energy of the electrons. At the energies measured by our instrument, these energy losses suppress the flow of particles from distant sources, which helps nearby sources stand out," he added.

The scientists point out, however, that there are few such objects close to our solar system.

"These results may be the first indication of a very interesting object near our solar system waiting to be studied by other instruments," Wefel said.